If you liked him as Bennifer . . . you'll love him as Benator! That's the hot new idea being tossed around by Virginia Democrats, who are desperately searching for a big name to challenge the reelection bid of rising GOP star Sen. George Allen next year, now that outgoing Gov. Mark Warner has ducked out. Why, who should happen to be pondering a move to Thomas Jefferson country but a certain square-jawed media magnet with a taste for liberal politics and millions to spend on it . . . Ben Affleck! Star of "Gigli" and the J.Lo tab romance,...